Control system



CONTROL SYSTEM Filed May 5, 1939 INVENTOR W M M ATTO R N EY PatentedFeb, 25, 1941 PATENT QFFECE CONTROL SYSTEM Application May 5, 1939,Serial No. 271,862

8 Claims. (Cl. 192.02)

This invention relates toan electrically operated control for a motordriven feed shaft or screw for a machine tool so that theshaft or screwmay be rotated in, either direction and quickly stopped while the motorcontinues to ro= tate or prior to the motor coming to rest.

A primary object of the invention is to provide driving connections fora shaft or screw including a driving motor therefor having its armaturedirectly coupled to a magnetic clutch, the armature of the clutch beingconnected, preferably through gearing, to the shaft or screw.

A feature that enables me to accomplish the above named object is thatcontacts are opened and closed, as by a tracer, closure of eithercontact serving to start rotation of the motor in one or the otherdirection and also to simultaneously energize the clutch to drivinglyconnect the motor to the shaft. When either contact is opened, however,the clutch is instantly deenergized so that the shaft or screw isdisconnected from the motor and the shaft therefore will not overrunwhile the motor may continue to rotate.

Another object of the invention is to operate the control for the motorand clutch through a reversing switch or relay, the contacts being on awalking beam so that but one contact can be closed at any one time,these contacts in turn controlling solenoid operated switches for themotor field circuit in reverse directions.

In any tracercontrolled machine the tracer for which controls movementsof a slide or other movable machine member, it is essential that thecontrol be extremely sensitive so that as the tracer moves over a modelor template the movable machine member may be promptly stopped when thetracer contacts with or moves away from the model. In the presentcontrol system this stopping of the movable member is efi'ected by thedeenergizing of a magnetic clutch. In the forming of many shapes inavertical milling machine or die sinker a reversal of-movement of themovable machine member is not required as this member may have to remainin a fixed position until movement of another member is completed.Thereafter the machine member may be required to move again in the samedirection so that reversal of the motor would not be required. Openingof a tracer contact therefore does not stop or reverse the rotation ofthe motor. This rotation continues until a further movement of thetracer contact effects closing of an opposite contact which againenergizes the clutch and rotatesthe motor in the reverse direction.

Another object of the invention is to simultaneously energize a clutchwhen motor connections are to be made to rotate the motor in eitherdirection, and when the shaft is to be stopped or have its rotationreversed, to disengage the clutch independently of the motor, thuspreventing overrun of shaft due to the motor continuing to rotate ortaking time to come to rest.

More particularly it is an object of the invention to control therotation of a shaft or screw from alternately opened and closed con-.

tacts such as employed in the tracer controlled machine as shown inpatent to Shaw,'1,683,58l granted September 4, 1928. With the above andother objects in view the invention may include the features ofconstruction and operation set forth in the following specification andillustrated in the accompanying drawing. In the accompanying drawingannexed hereto and forming a part of this specification I have shown theinvention embodied in electrical circuits for a machine of the typeshown in the above referred to patent, but it will be understood thatthe invention can be otherwise embodied and that the drawing is not tobe construed as defining or limiting the scope of the invention, the

claims appended to this specification being relied upon for thatpurpose. 7

In the drawing the figure shows a wiring dia gram for controlling themotor and clutch for stopping and for rotating a screw 'in'oppositedirections from contacts opened and closed by which is now deemedpreferable, but it will be.

understood that changes and modifications may be made within the scopeof the appended claims without departing from the spirit of theinvention.

Briefly and in its broadest aspect my invention may include: First, amotor; second, a magnetic clutch rotated directly therefrom; third, ashaft or screw .drivingly connected to the armature of the clutch;fourth, a tracer, movement of which to and from a central position opensand closes contacts of relay circuits; and fifth, circuits controlled bysaid relay circuits for energizing said clutch and for closing fieldcircuits of said motor for rotation of the motor in either direction.

Referring more in particular to the diagram, the motor 10 may be of anysuitable type having its field windings supplied with current fromrotation therewith is a magnetic clutch l4 supplied with current i'rombrushes i5 engaging slip rings l6 on the clutch. The circuit for thebrushes l5 will presently be more fully described.

Adjacent the magnetic clutch body i4 is the armature |1 therefor mountedon a shaft I 8. this shaft i8 being drivingly connected to a shaft orscrew i9 as by means of the gearing 28. Armature |1 when the magneticclutch i4 is energized is drawn toward and forced to rotate with theclutch |4 so that screw I8 is rotated whenever the circuit for thebrushes I5 is closed and the motor I0 is rotated.

The motor I8 is rotated in opposite directions depending upon theconnections to its armature windings through lead wires 2| and 22connected through either of two solenoid switches 28 and 24 to a sourceof current by connections forming part of the control circuits formingthe present invention. These circuits will presently be more fullydescribed..

To energize the circuits for the magnetic clutch I4 and the armaturewindings of the motor 18 contacts 26 and 21 opened and closed bymovements of a tracer 28 are employed. The tracer 28 is shownfragmentarily only and its movementsfrom the position shown in thediagram oscillate a lever 29 which, as shown, is grounded.

As the operation of the tracer 28 upon the lever. 28 and the mounting ofthe lever 29 are or may be similar in every way to the constructionshown in Fig. 16 of the above referred to patent, further description isnot thought to be necessary. The circuits for the clutch |4 includeconductors 45, 28,2l and 82, the brushes l5, conductor 22, relayoperated switch 24 and conductor 25. Conductors 45 and 25 are connectedto the main leads L+ and L- respectively. With the tracer in theposition shown, switch 34 is drawn to its closed position by solenoid 26which is energized by current from a small grounded generator 21'throughconductors 28, 89, contactor 28 to the grounded lever 29. With thecontact 21 closed a circuit is closed to solenoid 48 adjacent solenoid26 through conductors 28 and 4| to the grounded lever 29. .With eithercontact 26 or 21 closed,

therefore, switch 24 will be closed and the clutch 2| and z: thesolenoid for switch 2: or 24 is closed by a circuit including one or theother of contactors 42 or 42 of a reversing switch connected by awalking arm 44 so that but one contact 42 or 42 may be closed atany-instant. The

coils 52 and 52 for contactors 42 and "respectively are connected to theleads L+ and L- by conductors 45, 46, 41, 48. resistance 49 and conv sothat the motor 18 will rotate in the opposite direction.

Coils 52 and 52 of the switches 42 and 42 are connected in a circuit tothe main leads L+ and L-by conductors 45, 46, 41, 48, resistance 49 andconductors 58 and 5|. To short circuit either coil 52m 52, circuitsincluding switches 58 and 59 are employed. Switch 58 is closed by acircuit from generator 21 through conductors 88, 68, 8|, solenoid 62 andconductor 62 to the contact 26 and grounded lever 28. Whenever contact26 is closed, therefore, the motor will be rotated in one direction.With contact 21 closed, switch 58 will be closed by a circuit fromgenerator 21 through conductor 68 to the solenoid 64, and conductor tothe groundedlever 29. With either switch 58 or 58 closed, a circuit willbe closed to short circuit one or the other of the contactor coils 52 Or52. Switch 58 when closed short circuits coil 52 and switch 58 whenclosed short. circuits coil 52.

In operation when a tracer controlled contact 26 or 21 is opened therelay 24 for the clutch circuit is promptly opened which instantlydeenergizes the magnetic clutch i4 and breaks the connection between themotor l8 and screw l8. Further rotation of the screw is thereforediscontinued. The contactors 42 and 42 of the reversing switch willremain in the same position for the reason-that, although switch "or 58has opened and both coils 52 and 52 are energized,

the closed contactor will be held closed for the reason that its air gapis less and its flux greater than that. I

With the tractor 28 moved sufficiently in any direction from theposition shown in the diagram the contact on the opposite side of thelever 28 is closed. Closure of this opposite contact closes a circuit todraw the relay 24 down to close the magnetic clutch circuit so that theclutch i5 is therefore reenergized. .This movement of the tracer 28 alsocloses relay 58 and raises contactor 42 at the left of the walking beam44 by short circuiting the opposite coil. The solenoid switch 22 at theleft of the walking beam 44 is therefore closed which closes thearmature circuit to leads 2|, 22 in the opposite direction. Rotation ofthe motor therefore takes place in the opposite direction and thisrotation continues so long as this tracer contact 21 in the diagram isclosed. As soon as either tracer contact26 or ,21 is opened the clutchI4 is deenergized but rotation of the motor M will continue in the samedirection until the opposite contact on the tracer lever 28 is closed.Continued rotation of the motor, however, has no effect upon rotation ofthe shaft i9, as the clutch |5 has been deenersized.

What I claim is:

1. A. control system comprising in combination, a motor, a magneticclutch drivingly connected therewith, an armature for said'clutchadjacent thereto and connected to a shaft for rotation therewith wherebyrotation of said armature will rotate said shaft, tracer controlledcontacts, circuits controlled by said contacts to simultaneouslyenergize said clutch and start rotation of said motor in a predetermineddirection, and circuits to deenergize said clutch when said contacts aresimultaneously opened.

2. A control system comprising in combination, a motor, a magneticclutch drivingly connected therewith, amarmature for said clutchadjacent thereto and connected to a shaft for rotation therewithwherebirotation of said armature will rotate said shaft, tracercontrolled contacts, relays controlled by said contacts to open andclose circuits to simultaneously energize said clutch and start rotationof said motor in a predetermined direction, and relay controlledcircuits to deenergize said clutch when said contacts are simultaneouslyopened.

3. A-control' system comprising in combination, a motor, a magneticclutch drivingly connected therewith, an armature for said clutch nectedtherewith, 'an armaturefor said clutch adjacent thereto and connectedto. a shaft whereby rotation of said armature with said clutch willrotate said shaft,-. tracer controlled contacts, circuits controlled bysaid tracer contacts to simultaneously energize said clutch and startrotation of said motor in a predetermined direction, said circuitsdeenergizing said clutch when said contacts 'are simultaneously-open,

and circuits controlling said motor rotation andreversing saidrotationwhen one tracer contact is opened and the opposite contact is closed.

5. A control system comprising in combination, a motor, a magneticclutch drivinglyconnected therewith,-an armature for said clutchadjacent thereto and connected to a shaft whereby rotation of saidarmature will rotate said shaft,' tracer controlled contacts, circuitscontrolled by said tracer contacts to simultaneously energize saidclutch and start rotation of said motor in a predetermined direction,j.and circuits controlled by the opening of one of said contacts todeenergize said clutch while said motor continues to rotate in the samedirection.

6. A control system comprising in combinanected therewith, an' armaturefor said clutch adjacent thereto and connected to a shaft wherebyrotation of said armature will rotate said shaft, tracer controlledcontacts, circuits controlled by said tracer contacts to simultaneouslyenergize said clutch and start rotation of said motor in a predetermineddirection, and circuits controlled by the opening of 'one of said"contacts to deenergize said clutch while said motor continues to rotatein the same direction, saidcircuits when an opposite tracer contact isclosed being adapted to'reenergize said clutch and rotate themotor inthe reverse direction.

'7. A control system comprising in combinetion, a motor, a magneticclutch drivingly connected therewith, anarmature for said clutchadjacent thereto and connected to a shaft whereby rotation of saidarmature will rotate said shaft, tracer controlled contacts, circuitscontrolled by said tracer contacts to simultaneously energize saidclutch andjstart rotation of said motor in a predetermined direction,circuits'c'ontroiled by the opening of oneof said contacts to deenergizesaid clutch while said motor continues to -rotate in the same directionas long as both contacts are open, and circuits to reenergize saidclutch and rotate said motor in the reverse direction when said oppositecontact is closed.

8. A control system comprising in combination, a motor, a, magneticclutch driving'ly. connected therewith, an armature for said clutchadjacent thereto and connected to a shaft controlled by said tracercontacts to simultaneously energize said clutch and start rota-.

tion of said motor in a predetermined direction, and circuits controlledby the opening of one of said contacts to deenergize said clutch whilesaid motor continues to rotate in the same direction as long as bothcontacts are open, said circuits when an opposite tracer contact isclosed being adapted-to reenergize said clutch. and rotate the motor inthe reverse direction. I ROBERT D. SHAW.

tion, a motor, a magnetic clutch drivingly con- I whereby rotation ofsaid armature will rotate said shaft, tracer controlled contacts,circuits

